Venetian blind with worm gear tilting assembly

ABSTRACT

A venetian blind having a head rail of small transverse dimensions, containing a tilt rod rotatably supported therein for tilting the slats of the blind through tapes operatively connected to the tilt rod, and a worm gear mechanism for turning the tilt rod. The gear of this mechanism is in elongated cylindrical form, having a tooth-bearing portion and a shank portion with an axial socket for receiving and engaging one end of the tilt rod. The socket terminates short of the toothed portion, so that a desired tooth depth and tilt rod thickness can both be accommodated without unduly reducing the thickness of the socket-defining wall in a gear of small overall diameter. The gear is restrained by a housing against axial displacement, and the inner end of the socket acts as a stop at one end of the tilt rod, while a fixed stop plate mounted on a lift cord lock mechanism adjacent the other end of the tilt rod in the head rail cooperates with the socket end to prevent axial displacement of the tilt rod.

United States Patent Englund et al.

[ Nov. 11, 1975 1 1 VENETIAN BLIND WITH WORM GEAR TILTING ASSEMBLY [75] Inventors: James A. Englund; Basil H. Buck,

both of Middlesex, NJ.

[73] Assignee: Alcan Aluminum Corporation,

Cleveland, Ohio [22] Filed: Apr. 30, 1974 [21] Appl. No.: 465,553

[52] US. Cl. 160/176 [51] Int. Cl. E06B 9/00 [58] Field of Search 160/166-178; 74/439 [56] References Cited UNITED STATES PATENTS 1.173289 2/1916 McKee et al. 74/439 2.127330 8/1938 Findell i i 160/176 2.534.080 12/1950 Stuber et a1 160/178 R 2599384 6/1952 Bennett 160/176 3.269.453 8/1966 Vecchiarel1ietal......i 160/176 3.425,479 2/1969 Lorentzen et a1 160/176 Primary Examiner-Paul R. Gilliam Assistant Examiner-V. Sakran Attorney, Agent, or FirmCooper, Dunham, Clark, Griffin & Moran 5 7] ABSTRACT A venetian blind having a head rail of small transverse dimensions, containing a tilt rod rotatably supported therein for tilting the slats of the blind through tapes operatively connected to the tilt rod, and a worm gear mechanism for turning the tilt rod. The gear of this mechanism is in elongated cylindrical form, having a tooth-bearing portion and a shank portion with an axial socket for receiving and engaging one end of the tilt rod. The socket terminates short of the toothed portion, so that a desired tooth depth and tilt rod thickness can both be accommodated without unduly reducing the thickness of the socket-defining wall in a gear of small overall diameter. The gear is restrained by a housing against axial displacement, and the inner end of the socket acts as a stop at one end of the tilt rod, while a fixed stop plate mounted on a lift cord lock mechanism adjacent the other end of the tilt rod in the head rail cooperates with the socket end to prevent axial displacement of the tilt rod.

8 Claims, 20 Drawing Figures US. Patent Nov. 11, 1975 SheetlofS 3,918,513

U.S. Patent Nov.11, 1975 Sheet20f5 3,918,513

US. Patent Nov. 11,1975 Sheet30f5 3,918,513

US. Patent Nov. 11,1975 Sheet40f5 3,918,513

US. Patent Nov. 11, 1975 SheetS f 5 3,918,513

VENETIAN BLIND WITH WORM GEAR TILTING ASSEMBLY BACKGROUND OF THE INVENTION This invention relates to venetian blinds, and in a specific sense to venetian blinds incorporating, within a head rail, a new and improved assembly for tilting the slats of the blind, capable of embodiment in a durable, reliably operable and easily assembled structure of unusually small dimensions.

In a conventional venetian blind, a bottom rail and an array of slats are suspended beneath a head rail which is fixedly mounted to a wall or thelike adjacent the top of a window. The slats and bottom rail may be suspended by plural tapes from a tilt rod mounted within the head rail for rotation to move the tapes in a manner that effects tilting of the rail. For example, the tilt rod may be driven by a worm-gear assembly within the head rail, the worm of such assembly being turned manually by a depending cord or other means; such assemblies are advantageous in preventing backlash, because the worm can drive the gear of the assembly to tilt the slats as desired, but the gear cannot drive the worm, which thus effectively locks the slats in a desired tilted position. Lifting of the blind is accomplished by means of a lift cord having ends anchored to the bottom rail, and extending upwardly therefrom through the slats and the head rail and through a suitable cordlocking mechanism mounted within the head rail, the free control loop of the lift cord depending from the locking mechanism so as to be manually accessible.

Venetian blinds having very narrow (e.g. one inch wide) slats and narrow, stringlike tapes have won wide acceptance in recent years for aesthetic reasons, as providing a less obtrusive, more attractive appearance (and requiring less space) than older forms of venetian blinds with wide slats and tapes. However, comparable reduction in width of the head rail has not been satisfactorily achieved, owing to difficulties in reducing the size of the operating mechanism therein contained. It is desirable to provide a head rail as narrow, for instance, as the one-inch slats, not only because of aesthetic considerations but also to enable mounting of the head rail in a narrowly constricted space such as a narrow, downwardly opening wall pocket adjacent the top ertured gear body, especially at the localities of the valleys between the teeth, tending undesirably to weaken the gear. Another problem presented by a conventional tilting assembly is that the tilt rod may slide axially with respect to the gear, and may indeed become dislodged from its operative engagement therewith, e.g. during transport or handling of the blindsprior to installation.

SUMMARY OF THE INVENTION dental dislodgement by displacement in an axial direcof a window; but heretofore head rails have had to be i made substantially wider than this desired dimension.

By way of illustration of the difficulties involved in attempting to achieve a venetian blind operating mechanism of reduced size, the tilting assembly of a conventional blind commonly includes a tilt rod e.g. of square cross-section extending through and beyond a central aperture of corresponding (e.g. square) shape formed in the gear of the worm-gear tilting mechanism, so that the tilt rod turns with the gear. The overall diameter of the gear, and the size of the necessary support structures therefor, limit the attainable reduction in head rail dimensions; yet mere miniaturization (i.e. proportionate reduction of all dimensions) would result in undesired weakening of the parts and/or prevention of satisfactory operation. In particular, for a given wormgear ratio, effective meshing action requires a certain minimum tooth depth despite small gear diameter. Reduction in tilt rod thickness is limited by considerations of strength and rigidity. Given these constraints, decrease in overall gear diameter would necessarily involve a decrease in radial thickness of the centrally ap- To these and other ends, the present invention broadly contemplates provision of improvements in a venetian blind assembly of the general type having slats tiltably supported by tapes; a head rail; a tilt rod within the head rail and operatively connected to the tapes; means mounted in the head rail for supporting the tilt rod for rotation to move the tapes to tilt the slats; and a worm-gear tilting mechanism, mounted in the head rail, including a gear connected to the tilt rod, a worm meshing with the gear, a housing for supporting the worm and gear, and manually movable means connected to the worm for turning the worm to drive the gear and tilt rod. Specifically, significant features of the invention reside in the structure and arrangement of elements of the tilting mechanism in this combination.

Thus, in accordance with the invention, the gear is of elongated, generally cylindrical configuration, disposed in coaxial relation to the tilt rod at one end thereof, and includes a first shank portion journalled in the housing and a second portion, disposed in side-by-side relation to the shank portion along a common axis and bearing on its outer periphery a plurality of gear teeth with which the worm meshes. The first or shank portion has a socket formed coaxially therein and opening at one end thereof for receiving the end of the tilt rod and engaging the same so that the tilt rod rotates with the gear. This socket terminates inwardly in a seat within the shank portion; i.e. it is entirely contained within the shank portion and does not extend at all into the toothed portion of the gear. In other words, the shank portion constitutes an axial extension of the gear, .within which extension the socket for the tilt rod is wholly confined. As a result, desired reduction in overall diameter of the gear (and consequent small size of the tilting mechanism and of the head rail that contains it) may be achieved in a sturcture that provides requisite tooth depth and accommodates a tilt rod of adeinclude a further shank portion coaxial with the.

toothed portion and disposed on the side thereof opposite to the first shank portion. Each shank portion may have an enlarged extremity; the housing may include opposed fixed end walls with openings through which the two shank portions extend, inwardly of their enlarged extremities, so that these extremities in cooperation with the housing walls (which are fixed in relation to the head rail) prevent axial displacement of the gear in either direction. Advantageously, for ease of assembly, the toothed portion and both shank portions may all have the same overall diameter, and the gear may comprise two interfitting bodies (one including one shank portion, and the other including the toothed portion and the other shank portion) which are respectively inserted through the openings in the two housing end walls, i.e. into interfitting relation with each other.

The seat of the socket, in the gear just described, serves as a stop at one end of the tilt rod, preventing axial displacement of the tilt rod toward the gear. As an additional specific feature of the invention, a lift cord lock mechanism (for controlling operation of alift cord connected to a bottom rail of the blind, to lift the blind) may be fixedly mounted in the head rail, just beyond the other end of the tilt rod and may include a stop plate, positioned in facing relation to the tilt rod end, for preventing axial displacement away from the gear. The latter plate thus cooperates with the described socketed gear to prevent dislodgement of the tilt rod by axial motion thereof in either direction, as well as protecting the lift cord lock mechanism from damage or interference by the tilt rod which might otherwise slide into that mechanism because of the absence of clearance space in a head rail of small width.

The tapes, each of which has two parallel vertical stringlike elements, may each be secured (at the upper ends of such elements) to a roll supported in a bearing or cradle mounted within the head rail, for rotation about the tilt rod axis. The tilt rod, which is preferably hexagonal in cross-section, extends through bores in these rolls (which engage the rod forrotation therewith); i.e. the tilt rod is effectively joumalled in and supported by the tape roll cradles, and the weight of the slats, transmitted by the tapes, is supported by the cradles rather than by the tilt rod, thereby avoiding excessive load on the tilt rod such as might interfere with ease of tilting operation especially with a tilting mechanism of small size.

Additional specific features of the invention reside in the structure of the tape rolls. Each is formed in two parts: a molded plastic body, having a shank with an axial bore for the tilt rod and a central flange with two peripheral notches to receive the ends of the two tape elements; and a molded plastic cap, press-fittable over the flange from one side thereof to enclose and retain the tape ends, and having an opening in its end through I which the shank protrudes. The tape element ends bear ferrules for retention in the notches. A key projection, formed on the flange in opposed relation to the tapeend-receiving notches and received in a notch of the cap skirt, provides a visual indication of the angular orientation of the roll and tape ends. These features provide special advantages with respect to ease of assembly.

Thus, with the present invention, there is achieved a venetian blind operating mechanism that can readily be dimensioned to fit inside a head rail e.g. of 1 inch square cross-section, without sacrifice of durability and effectiveness of operation.

Further features and advantages of the invention will be apparent from the detailed description hereinbelow set forth, together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary perspective view, partly broken away, of a venetian blind embodying the present invention in a particular form;

FIG. 2 is an enlarged side elevational view of the tilting mechanism of the device of FIG. 1;

FIG. 3 is an end elevational view of the FIG. 2 mechanism;

FIG. 4 is an enlarged sectional view taken along line 44 of FIG. 2;

'FIG. 5 is a similarly enlarged sectional view taken along line 5-5 of FIG. 3;

FIG. 6 is a view, similar to FIG. 3, of a modified form of the tilting mechanism of the invention;

FIG. 7 is a view, similar to FIG. 2, of the FIG. 6 mechanism;

FIG. 8 is an enlarged sectional view taken along line 8-8 of FIG. 6;

FIG. 9 is a sectional view taken along line 9-9 of FIG. 8;

FIG. 10 is a sectional view taken along line 10-10 of FIG. 9;

' FIG. 11 is a side elevational view of a tape roll and cradle, and associated elements, in the blind of FIG. 1; FIG. 12 is a view taken along line 12-12 of FIG. 11; FIG. 13, 14 and 15 are perspective views illustrating successive steps in attaching a tape to a tape roll of the blind of FIG. 1;

FIG. 16 is a fragmentary view taken along the line 16-16 of FIG. 12;

FIG. 17 is a side elevational view of the cord lock mechanism in the blind of FIG. 1;

FIG. 18 is an end elevational view of the cord lock mechanism;

FIG. 19 is an enlarged sectional view taken along line 19-19 of FIG. 18; and

FIG. 20 is a detail view taken along line 20-20 of FIG. 19.

DETAILED DESCRIPTION The invention will be described as embodied in a venetian blind wherein the head rail, as well as the array of slats, is not more than about 1 inch wide, since the provision of a durable and effective operating mechanism within a head rail of such relatively small dimension constitutes an especially important advantage thereof.

Referring to FIG. 1, the invention in its illustrated embodiment comprises a venetian blind structure 10 including the customary array of horizontal slats 11 and bottom rail 12 suspended below a head rail 14 which contains the operating mechanism of the blind structure and which is adapted to be mounted as by means of suitable brackets (now shown), e.g. adjacent the top of a window. As shown, the head rail 14 is an upwardly opening metal channel member of square cross section (e.g. 1 inch square), having a metal end lock 15 pressfitted into each end. The slats and bottom rail are suspended at spaced locations along their length by a pair of tapes 16 which are respectively secured at their upper ends to a pair of tape rolls 18 respectively supported within the head rail by cradles 20 for rotation about a common axis parallel to the long dimension of the head rail. Also mounted within the head rail, adjacent one end thereof, is a tilting mechanism 22 from which a tilt rod 24 extends (within, and longitudinally of, the head rail) through the tape rolls, along their common axis, to effect rotation of the tape rolls for tilting the slats upon operation of the tilting mechanism. A lift cord 26, having opposite ends 26a and 26b secured to the bottom rail 12 at spaced locations, and extending upwardly through the slats and through the head rail, is passed through a lift cord lock mechanism 28 mounted within the head rail adjacent the end thereof remote from the tilting mechanism. The central portion 29 of the lift cord depends from cord lock 28 for manual operation to raise or lower the blind, while the tilting mechanism 22 has a depending wand 30 or cord 31 (FIG. 6) for manual operation to tilt the slats, all as hereinafter further described.

Each of the tapes 16 is a so-called string or cable tape, comprising two parallel vertical stringlike (e.g. braided) flexible tape elements 16a and 16b interconnected, at regularly vertically spaced locations, by a plurality of flexible horizontal ladders 16c (FIG. 12) for individually supporting the slats 11. At its lower end, each tape is secured in a suitable and eg generally conventional manner (not shown) to the bottom rail 12; the slats are inserted between the elements 16a and 16b of each tape in such arrangement that each slat rests on and is supported by corresponding ladders 160 of the two tapes, at spaced locations intermediate the slat ends, in a horizontal position. Above the uppermost slat 110, the two elements 16a and 16b of each tape extend for a predetermined equal distance without interconnecting ladders, and are secured to a tape roll as hereinafter explained. When the tape rolls are rotated, one of the elements 16a or 16b of each tape is raised while the other such element is lowered; this causes simultaneous tilting of all the ladders 16c, and consequent tilting of the slats supported thereon, in a common direction about axes parallel to the long dimension of the slats. To ensure proper tilting of the uppermost slat 11a, the ends of the tape ladders 16c supporting that slat may be anchored to the slat by means of metal clips or tape spacers 33 (FIGS. 12 and 16) which extend beneath slat 11a and the associated ladders 16c and have tabs 33a gripping the slat edges on either side of the ladder.

Each tape roll 18 comprises an integral molded rigid plastic body 35 and a molded rigid plastic cap 36 (FIGS. 11-15). For use with a tilt rod 24 of hexagonal cross-section, the body 35 has an axially elongated cylindrical shank 38 having an axial bore 39 of hexagonal cross-section dimensioned to receive rod 24 suffi- 'ciently snugly so that the body 35 rotates with the rod '24. A generally annular flange 40, formed integrally with the shank 38, projects outwardly therefrom at a central locality on the shank; this flange 40 has two peripheral notches 41 and also bears a peripheral key projection 42 positioned in opposed relation to the notches. Cap 36 is dimensioned to fit snugly over flange 40, with key projection 42 received in a key notch 43 formed in the edge of the cap skirt, and with one end 38a of shank 38 protruding through a circular opening 45 in the end 46 of the cap. To arrest the cap against displacement toward flange 40, shank 38 may have a shoulder 47 formed intermediate end 38a and flange 40 for engaging the inner surface of the cap end.

The attachment of a tape 16 to a tape roll 18 is illustrated stepwise in FIGS. 13-15. Initially, small metal ferrules 48 are clamped onto the free upper ends of the two vertical tape elements 16a and 16b, and these ends are inserted in the notches 41 of the flange 40, with the ferrules 48 disposed on the side thereof toward shank end 38a (FIG. 13) so as to retain the tape ends in the notches and to be enclosed by the cap 36, which may then be placed on the body. With the shank 38 disposed horizontally and the notches positioned below it (FIG. 14), the elements 16a and 16b are lifted above the shank, twisted over as indicated at 49 (FIG. 15), and allowed to drop below the shank. The described structure of the parts, and the use of the ferrules 48, permits rapid and secure attachment of the tapes to the tape rolls (i.e. in such manner that rotation of the rolls tilts the tape ladders and slats) by the foregoing succession of steps.

The two tape rolls 18, having the two tapes 16 re spectively attached thereto, are mounted on rod 24 (by insertion of the rod through their axial bores 39) in spaced relation to each other intennediate the ends of the rod and with their respective key projections 42 oriented in the same direction, i.e. in the same angular relation to a given flat side face of the rod 24. Typically,

the two key projections 42 of the two tape rolls are both oriented upwardly. The key projections provide a convenient visual means for thus assembling the tape rolls on the rod in identical angular orientation, with specific reference to the position of the notches 41, so that rotation of rod 24 about its axis will effect an identical tilting movement of both tapes.

Each of the tape roll cradles 20 is a unitary rigid metal member having opposed upstanding end walls 50 and 51 formed with outwardly flaring semicircular notches 52 for receiving and supporting the opposed ends 38a and 38b of the shank of a tape roll in such manner as to permit rotation of the tape roll about its axis. Each tape roll cradle further includes a base portion 54 which rests on the floor or web 14a of the head rail 14 and has a transverse slot 54a positioned for register with a corresponding slot 14b formed in the head rail web. As shown'in FIGS. 1, 11 and 12, slot 54a is formed with a depending lip 54b that fits within the periphery of the head rail slot 14b when the cradle is mounted on the head rail. Each cradle is fixedly secured to the head rail by a bent tab 50a (FIG. 11) which projects downwardly from the cradle adjacent end wall 50 for insertion through a small slot in the head rail web, and by blind rivet 50b inserted through the web and the base 54 between slot 14b and end wall 51 of the cradle. The positions of the two cradles 20 and the associated slots 14b in the head rail web are spaced along the central portion of the head rail intermediate the respective locations of the tilting mechanism and cord lock.

After the cradles 20 are mounted in the head rail (by sliding them endwise along the rail to the positions of the two slots 14b respectively, inserting and bending the tabs 50a and riveting), the two tape rolls 18, mounted on rod 24 and having the tapes 16 attached to and depending therefrom, are seated in the cradles. The tapes respectively drop downwardly from the tape rolls through the slots 54a, i.e. through and below the head rail web. These tapes, as stated, carry the bottom rail and slats of the assembly; thus the weight of the slats and bottom rail is transmitted through the tape rolls 18. Since the opposite ends 38a and 38b of the tape roll shank are supported by the cradle end walls 50 and 51, i.e. seating in the semicircular notches 52, this weight is supported by the cradles and not by rod 24. The tape rolls and their associated cradles effectively constitute bearings supporting rod 24 at intermediate locations for rotation. The described arrangement whereby the blind assembly is supported by the tape rolls and cradles and not by the tilt rod is important for avoidance of an excessive load on the tilt rod such as might interfere with desired operation of the tilting mechanism, especially in view of the dimensional limitations imposed on the operating parts of the tilting mechanism (hereinafter described) by the small size of the head rail.

Each cradle end wall 51 has a tab 51a above its semicircular notch 52. This tab is initially parallel to the tilt rod, to facilitate mounting of the tape rolls in the cradles, but may thereafter be bent transversely of the tilt rod as shown in FIG. 12 to prevent upward dislocation of the tilt rod and tape roll.

Each cradle 20, as shown in FIGS. 1 1 and 12, also has low side walls 57 and 58 in which are journalled a small steel roller 60 on the side of slot 54a toward the cord lock mechanism 28. The two ends 26a and 26b of lift cord 26 respectively extend from the cord lock mechanism through the head rail over the rollers 60 of the two cradles and then downwardly, through the cradle slots 54a and through transverse slots 62 formed in each of the slats in register with the tape positions, to the bottom rail, to which the cord ends are securely fastened. The rollers 60 prevent excessive friction between the lift cord and the cradles. Openings 51b are provided in the cradle end walls 51 for passage of the lift cord therethrough; these openings as shown in FIGS. 11 and 12 have inwardly flared lips to provide smoothly rounded surfaces again for minimization of friction between the cradle wall and cord.

The lift cord lock mechanism 28 (FIGS. 17-20) includes a rigid metal housing 64 fixedly secured to the head rail web 14a in the same manner as the cradles 20, i.e. by means of a bent tab 64a and blind rivet 64b,

' adjacent the right-hand end of the head rail as seen in FIG. 1. Specifically, housing 64 is positioned for register with an opening 66 formed in the head rail at the angle of web 14a and the front wall of the head rail, to accommodate the lift cord. Housing 64 includes front and rear side walls 67 and 68 oriented in parallel planes diagonal to the vertical side walls of the head rail. A wooden roller 70 is journalled in the walls 67 and 68, and a cylindrical pin 72 has its ends slidably received in slots 74 of these walls of housing 64 so as to be axially parallel with roller 70 and to be slidable upwardly toward and downwardly away from a position generally tangent to the roller 70. Each of the slots 74 in the housing walls 67 and 68 is formed with an outwardly flaring lip 74a on one side (as best seen in FIG. to provide a bearing surface for enlargements 76 and 77 respectively formed at opposite ends of the pin; thus as the pin slides (in a direction perpendicular to its axis) in the slots 74, it is retained against axial movement by enlargements 76 and 77, yet without wear on the walls 67 and 68. The pin 72 has a ridged outer surface 78 for frictional engagement with the two end portions of lift cord 26, which pass between the pin and the roller 70.

The looped central portion 29 of the cord 26 depends from the housing 64 through a slot 80 formed in a lower wall portion of the housing and thence through the opening 66 in the head rail; to maintain the two end portions of the lift cord properly separated, a separating pin 82 may be mounted in the housing immediately beneath and parallel to slot 80, the opposite end portions of the cord 26 being respectively disposed on opposite sides of this pin. When the looped central portion of the cord 26 is pulled manually downward, as may best be understood from FIG. 19, the pin 72 is caused to slide downwardly in slots 74, i.e. away from the roller 70, releasing the cord 26; hence a continued downward pull on the cord lifts both ends of the cord (which are secured to the bottom rail 12) thereby raising the blind. Upon release of cord 26, the weight of the blind acting on the cord ends attached to the bottom rail tends to pull the cord upwardly over roller 70, but such cord motion causes the pin to slide upwardly until the cord is tightly clamped between the pin and the roller 70. The cord is thus arrested and locked against undesired descent of the blind.

As a particular feature of the invention in a specific aspect thereof, the cord lock housing 64 includes an end plate 84, fixedly disposed on the end of the housing facing the tape rolls and cradles within the head rail, and having a curved upper lip 84a over which both end portions of the lift cord 26 pass to the cradles 20. The curvature of the lip 84a prevents undesired friction between the lift cord and the plate 84. As best seen in FIGS. 17-19, plate 84 is positioned to be abutted by the free end of the tilt rod 24, i.e. the end thereof remote from the tilting mechanism 22, to prevent axial movement of the tilt rod 24 beyond the position of plate 84. In other words, plate 84 acts as a stop to hold the tilt rod in place against accidental dislodgement in an axial direction.

Further important features of the invention reside in the structure and arrangement of the tilting mechanism, now to be described. As shown in FIGS. 2-5, the mechanism 22 includes a rigid metal housing 86, secured (in the same manner as cradles 20) by a bent tab 87 and blind rivet 87a to the web of the head rail 14 in register with an opening 88 formed in the head rail at the angle of the head rail web and front wall adjacent the end of the head rail remote from the cord lock mechanism. Housing 86 has spaced vertical end walls 90 and 91 respectively having central circular openings 92 and 93, each formed with a laterally flared lip 94, and both disposed in coaxial relation to the tilt rod 24,

so as to constitute bearings for a gear 96 to which the tilt rod is connected.

The gear 96 is an axially horizontal, elongated, generally cylindrical body extending through the housing and rotatably supported by the lips 94 of housing end walls 90 and 91. A plurality of gear teeth 98 (e.g. eight teeth, FIG. 4) are formed on a central portion of the gear, within the housing 86, for meshing engagement with a worm 100 also journalled in the housing 86 for rotation about an axis lying in the plane of rotation of gear 96. The worm and gear are adapted to constitute an antibacklash arrangement for rotating the tilt rod; i.e. rotation of the worm turns the gear, but the worm cannot be driven by the gear. The design of such an antibacklash worm and gear system is well known to those skilled in the art.

As a particular feature of the invention, a socket 102 tilt rod 24 is formed in one end of the gear 96, coaxially therewith but displaced entirely to one side of the location'of gear teeth 98, so that no portion of the socket extends through that part of the gear which bears the teeth. Specifically, the socket extends through the smooth cylindrical shank portion 96a of gear 96 which is located to the right of teeth 98 as seen in FIG. 5, to such depth as to intersect the plane of housing end wall 91 (so that the end of tilt rod 24, when inserted in the socket, projects through wall 91 but stops short of the toothed region of the gear periphery; and the outer diameter of the latter toothed region (i.e. the diameter of the locus of the crowns of the gear teeth) is the same as the outer diameter of the cylindrical shank 96a extending through wall opening 93. In this way, the requisite gear tooth depth is accommodated (and the tilt rod end can be properly supported) without excessively reducing the thickness of the tilt rod or the gear wall as would be the case if the tilt rod socket extended through the tooth-bearing portion of a gear having the dimensional constraints imposed by the desired small width of the head rail. Socket 102 is so dimensioned that rotation of the gear 96 causes rotation of the tilt rod 24 therewith.

At its inner extremity, adjacent the toothed portion of the gear but on the same side thereof as the end of the gear through which the socket opens, the socket 102 terminates in a seat 104. Engagement of the end of the tilt rod 24 with this seat within the socket prevents axial displacement of the tilt rod to the left as seen in FIG. 1. Thus the seat 104 cooperates with the cord lock housing plate 84 to prevent undesired displacement of the tilt rod in either axial direction. The distance between plate 84 and the facing socketed end of gear 96 is less than the length of the tilt rod, so that the plate 84 prevents dislodgement of the tilt rod from the gear socket.

In the embodiment of FIGS. 2-5, gear 96 is formed in two parts 106 and 108, each being a molded integral rigid body of glass-fiber-filled plastic. Gear part 106, which contains socket 102, includes an enlarged outer end 110 (through which the socket opens) larger in external diameter than opening 93 in wall 91, and shank 96a dimensioned to fit within opening 93. Gear part 108 also has an enlarged outer end 114, larger in external diameter than opening 92 of wall 90, and a cylindrical shank 116 which fits within opening 92. The inner end of shank 116 bears the gear teeth 98, the outer diameter of which is equal to that of the remainder of shank 116 so as to be insertable through opening 92, and has a small cylindrical central bore 1 18 for receiving, in press-fitted relation, a cylindrical projection 120 formed at the inner end of shank 96a of part 106. It will be understood that in assembling the tilt mechanism 24, the shanks of the parts 108 and 106 are inserted, in

coaxial facing relation, through the opposed openings 92 and 93 of housing end walls 90 and 91, until the projection 120 is tightly received within bore 118 and the enlarged portions 110 and 114 respectively abut the flared lips 94 of the two openings. The two parts 106 and 108 then constitute an effectively unitary gear body 96 which is prevented from axial displacement, relative to housing 86, by the end enlargements 110 and 114.

Also, in the embodiment of FIGS. 2-5, the gear part 108 has an axial socket 122 of hexagonal cross-section opening through the outer end thereof, i.e. through the end of gear 96 opposite to socket 102, and identical in dimensions and construction to the socket 102, so that the tilt rod 24 may be inserted into either end of the gear, thereby permitting use of the tilt mechanism at either end of the head rail. In addition, enlarged end 114 of gear part 108 bears a radially outwardly projecting lug 124 which engages a. cooperating projection 126 on housing end wall to limit rotation of gear 96 (and of tilt rod 24) in either direction. The lug 124 and projection 126 cooperatively constitute a stop arrangement for preventing excessive tilting motion of the tapes 16.

It will be understood that, by appropriate selection of the angular orientation of the tape rolls 18 on tilt rod 24 in relation to lug 124, i.e. during assembly, the blind slats may be made capable of tilting to a greater degree in one direction than in the other, if such is desired. Although a tilt rod of square or other grippable crosssection may be used, one advantage of using a hexagonal configuration for the tilt rod is that the hexagonal shape permits a greater number of different relative angular positions of the tape rolls and lug than does a rod of square cross-section. Another advantage of the hexagonal rod shape is that for a given rod thickness (minimum transverse dimension) and given external diameter of gear shank 96a, the minimum thickness of the socketed shank wall is greater than would be the case if the rod were of square cross-section.

Referring further to FIGS. 2-5, the worm is shown as journalled in top and bottom walls 127a and 127 b of housing 86, with its axis slanting forwardly and downwardly. The lower end 1128 of the wonn (which may be an integral metal element) is elongated, projecting through the head rail opening 88, and has a depending wand 30 (FIGS. 1) connected to it. Manual rotation of the wand turns the worm, driving gear 96 to rotate tilt rod 24 and tape rolls 18, and thereby to tilt the slats 11 in a direction determined by the direction of wand rotation.

A modified form 22' of the tilting mechanism is illustrated in FIGS. 6-10. In this modified mechanism, a rigid metal housing 130 (fixedly mounted on the web 14a of head rail 14 in register with the aforementioned opening 88) has parallel spaced vertical end walls 132 and 134 each formed with a central circular opening 136 or 137 defined by an inwardly flared lip 138. The openings 136 and 137, which are disposed in coaxial relation to tilt rod 24, serve as bearings for an elongated, generally cylindrical gear 140 having a central toothed portion 142 and a socketed end or shank portion 144 (receiving the end of the tilt rod) arranged in succession along a horizontal axis coincident with that of rod 24. I

Mechanism 22' of FIGS. 6-10 differs from the mechanism 22 of FIGS. 2-5 in being adapted to be operated by a cord 31. To this end, it includes an axially horizontal worm 146 journalled in front and rear walls 148 and 150 of housing 130 so as to mesh with the teeth of gear portion 142 to constitute an anti-backlash worm and gear system. The shank 152 of worm 146, at its forward end, is fixedly connected to a friction pulley 154 over which cord 31 is looped; as shown, pulley 154 is formed with tapered internal ribs 156 for gripping the cord 31 to prevent slippage of the cord relative to the pulley. The two ends of the cord project downwardly from the pulley through a grommet 158 held by a downwardly projecting portion 160 of housing 130. When one end or the other of cord 31 is pulled manually, worm 146 is rotated through pulley 154, driving gear 140 to tilt the slats 11.

In the mechanism 22 of FIGS. 6-10, there is also shown a modified form of the gear element. As best seen in FIG. 8, this gear 140 comprises an integral metal (e.g. zinc) body 162, having an enlarged end 164 outside the housing 130, smooth cylindrical shank 144 projecting into the housing through opening 137 of end wall 134, and toothed portion 142 within the housing, bearing eight gear teeth 142a with an outer diameter (from crown to crown of the teeth) equal to that of shank 144. Beyond portion 142, a reduced-diameter portion 166 of body 162 projects through opening 136 in housing wall 132 and is closely surrounded by a molded plastic sleeve 168 which seats rotatably in opening 136. Outwardly of wall 132, the sleeve has an enlarged flange 168a which cooperates with the enlarged gear end 164 to prevent axial movement of the gear relative to the housing. The outer extremity of gear portion 166 is hollow, and as shown at 170, is spun over a washer 172 to hold the washer against the outer face of sleeve 168 and to retain the gear body 162 and the sleeve in assembled relation. As will be apparent from FIG. 8, the gear body and sleeve are initially assembled by insertion (toward each other) through the respective housing openings 137 and 136. It will be understood that the illustrated orientation of the tilter gear element may be reversed; i.e. the gear element may be assembled in reverse (end for end) to provide alternate end blind tilting action.

Formed coaxially within shank 144 is a socket 174 of hexagonal cross-section, opening through gear end 164 for receiving the end of tilt rod 24, and terminating (within the housing, but short of toothed portion 142) in a seat 176 which prevents axial displacement of the tilt rod, i.e. in cooperation with fixed plate 84. This socket is so dimensioned that the tilt rod, when inserted therein, rotates with gear 130. As in the case of gear 96 described above, the arrangement of the socket 174 in axially displaced relation to the toothed portion 142 in gear 140 enables provision of requisite tooth depth, and reception of a tilt rod of desired thickness, in a gear structure of restricted external diameter, without undue reduction in thickness of the gear wall portion surrounding the socket, to afford the combined advantages of adequate strength and small size.

Also as in FIGS. 2-5, the enlarged gear end 164 may bear a lug 180 disposed for cooperation with a stop projection 18] formed on housing wall 134, to limit rotation of the tilt rod 24 in either direction by the tilting mechanism 22.

IN summary, then, as in the embodiment of FIGS. 2-5 the two parts 106 and 108 together constitute gear means comprising elongated, generally cylindrical structure having first and second shanks or shank portions respectively joumalled in the housing end walls and a toothed portion intermediate the two shanks or shank portions. so in the embodiment of FIGS. 6-10 the body 162 and sleeve 168 cooperatively constitute gear means comprising elongated, generally cylindrical structure having a first shank 144 (on body 162) and a second shank (constituted by sleeve 168 which is mounted on body portion 166) respectively joumalled in the housing end walls and a toothed portion 142 (also on body 162) intermediate the two shanks. In 6 each embodiment, the two shanks or shank portions respectively provided by the two parts of the structure (i.e. parts 106 and 108, in FIGS. 2-5, and body 162 and sleeve 168, in FIGS. 610) respectively have enlarged outer ends, to prevent axial displacement of the structure relative to the supporting housing when the structure is assembled therewith; and in each embodiment, the two-part construction of the structure facilitates such assembly by enabling insertion of the two parts respectively through the opposed end wall openings of the housing.

While a blind having two tapes, tape rolls and cradles has been shown, a larger number of these elements may be provided (spaced along the head rail) if desired to provide added support for very long slats. Additional lift cords, also accommodated within lock mechanism 28, may be used. If the number of tapes exceeds the number of points of lift cord attachment to the bottom rail, the rollers 60 may be omitted from those cradles through which no lift cord passes. The positions of the tilting and cord lock mechanisms may be reversed, or both may be placed adjacent the same end of the head rail, although with loss of feature of positive retention of the tilt rod against axial displacement by the cooperation of the gear socket and plate 84.

It is to be understood that the invention is not limited to the features and embodiments hereinabove specifically set forth but may be carried out in other ways without departure from its spirit.

We claim:

1. In a venetian blind assembly having slats tiltably supported by tapes, in combination,

a. a head rail;

b. a tilt rod, extending within and longitudinally of said rail and operatively connected to the tapes, for tilting the slats by rotation of the tilt rod about its axis;

c. means, mounted in said head rail, for supporting said tilt rod for rotation about its axis within said head rail;

(1. an elongated, generally cylindrical gear, disposed in coaxial relation to said tilt rod at one end thereof, said gear comprising i. a first shank portion having a socket formed coaxially therein and opening at one end thereof for receiving said one end of said tilt rod and engaging the same such that rotation of the gear effects rotation of the tilt rod, said socket terminating inwardly in a seat within said shank portion, and

ii. a second portion, disposed in side-by-side relation to said shank portion along a common axis therewith, bearing on its outer periphery a plurality of gear teeth, said socket terminating short of the position of said teeth along said common axis;

e. housing means mounted in said head rail for rotatably supporting said shank portion of said gear;

f. a worm joumalled in said housing means in meshing relation to said gear teeth for driving said gear; and

g. manually movable means connected to said worm for rotating said worm;

wherein the improvement comprises:

h. said gear further including another shank portion disposed on the side of said second portion opposite to said first portion coaxially therewith;

i. said housing comprising opposed fixed walls having coaxial openings in which said shank portions of said gear are respectively joumalled;

j. said second portion including said gear teeth having an external diameter equal to the minimum external diameter of said first portion; and

k. each of said shank portions projecting through the housing wall in which it is journalled and being enlarged externally thereof for preventing axial displacement of said gear relative to said housing.

2. A blind as defined in claim 1, wherein said gear comprises a first body including one of said shank portions and a second body interfitting with said first body and including said second portion and the other of said shank portions, said second portion including said gear teeth having an external diameter equal to the minimum external diameter of said other shank portion, and said bodies being respectively inserted through said housing wall openings into interfitting relation to each other.

3. A blind as defined in claim 1, further including a stop plate fixedly mounted in said head rail adjacent the end of said tilt rod remote from said gear for arresting axial displacement of said tilt rod away from said gear.

4. In a venetian blind assembly having a plurality of tapes, slats tiltably supported by said tapes, a bottom rail suspended by said tapes beneath said slats and a lift cord secured to the bottom rail at spaced points for lifting said bottom rail, in combination,

a. aa head rail;

b. a plurality of rolls respectively secured to the upper ends of said plurality of tapes within said head rail;

c. means, supported by said head rail, for engaging and supporting each of said rolls within said head rail for rotation about a common axis extending longitudinally of said head rail;

d. a tilt rod, extending through and beyond said rolls coaxially therewith, supported by and engaging said rolls such that rotation of said rod rotates said rolls;

e. means for locking said lift cord in a selected position, fixedly mounted within said head rail adjacent one end of said tilt rod, said locking means including a fixed plate facing said one end of said tilt rod for arresting axial displacement thereof toward said locking means;

f. gear means for rotating said tilt rod, comprising elongated, generally cylindrical structure having first and second shanks and a toothed portion intermediate said shanks aligned in succession along said common axis, said first shank having a socket formed coaxially therein and extending only within said first shank, said socket opening through an end of said first shank and terminating in a seat within said first shank, said toothed portion bearing gear teeth on its outer periphery, said socket receiving and engaging a second end of said tilt rod for rotation therewith and said seat arresting axial displacement of said tilt rod toward said gear, said socket terminating short of the position of said teeth along said common axis, and said toothed portion including said teeth having an external diameter equal to the minimum external diameter of said first shank;

a housing fixedly mounted in said head rail and rotatably supporting said first and second shanks of said gear means;

h. a worm journalled in said housing in meshing engagement with said teeth of said gear means for driving said gear means; and

i. manually movable means connected to said worm and depending from said head rail for rotating said worm;

j. said first and second shanks respectively projecting beyond said housing in opposite directions and respectively having enlarged ends external to said housing for preventing axial displacement of said gear means relative to said housing.

5. A blind as defined in claim 4, wherein said gear means structure comprises a first body including one of said shanks, a second body including the other of said shanks and said toothed portion, said toothed portion including said teeth having the same external diameter as said other shank one of said bodies further including a portion interengaging with the other of said bodies for holding said bodies in coaxial relation; and wherein said housing includes opposed end walls having coaxial circular openings through which said bodies are respectively inserted.

6. A blind as defined in claim 5, wherein said tilt rod and said socket are hexagonal in cross-section.

7. A blind as defined in claim 4, wherein each of said tapes comprises a pair of flexible stringlike tape elements each having a free upper end with a ferrule secured thereto; and wherein each of said rolls comprises i. a molded rigid plastic body including a cylindrical shank with an axial bore for receiving and engaging said tilt rod, and a central flange projecting radially of the shank, said flange having two peripheral notches, the upper ends of both elements of a tape being respectively inserted in said notches with said ferrules disposed on one side of said flange, said flange further having a radial projection positioned in opposed relation to said notches; and

ii. a molded rigid plastic cap press-fitted over said flange from said one side thereof for enclosing the ferrule-bearing ends of the tape elements, said cap having an end with a central opening through which said shank projects, said cap further having a skirt with a notch receiving said radial projection.

8. In a venetian blind assembly including a. a plurality of tapes each comprising a pair of flexible stringlike tape elements each having a free upper end with a ferrule secured thereto;

b. a plurality of slats tiltably supported by said tapes;

0. a bottom rail suspended by said tapes beneath said slats;

d. a lift cord secured to the bottom rail at spaced points for lifting the bottom rail;

e. a head rail;

f. a plurality of rolls respectively secured to the upper ends of said plurality of tapes within said head rail;

g. means, supported by said head rail, for engaging and supporting each of said rolls within said head rail for rotation about a common axis extending longitudinally of said head rail;

h. a tilt rod, extending through and beyond said rolls coaxially therewith, supported by and engaging said rolls such that rotation of said rod rotates said rolls;

i. means for locking said lift cord in a selected position; and

j. manually operable means for rotating said tilt rod; the improvement which comprises:

tion to said notches; and

1. each of said rolls further comprising a molded rigid plastic cap press-fitted over said flange from said one side thereof for enclosing the ferrule-bearing ends of the tape elements, said cap having an end with a central opening through which said shank projects, said cap further having a skirt with a notch receiving said radial projection. 

1. In a venetian blind assembly having slats tiltably supported by tapes, in combination, a. a head rail; b. a tilt rod, extending within and longitudinally of said rail and operatively connected to the tapes, for tilting the slats by rotation of the tilt rod about its axis; c. means, mounted in said head rail, for supporting said tilt rod for rotation about its axis within said head rail; d. an elongated, generally cylindrical gear, disposed in coaxial relation to said tilt rod at one end thereof, said gear comprising i. a first shank portion having a socket formed coaxially therein and opening at one end thereof for receiving said one end of said tilt rod and engaging the same such that rotation of the gear effects rotation of the tilt rod, said socket terminating inwardly in a seat within said shank portion, and ii. a second portion, disposed in side-by-side relation to said shank portion along a common axis therewith, bearing on its outer periphery a plurality of gear teeth, said socket terminating short of the position of said teeth along said common axis; e. housing means mounted in said head rail for rotatably supporting said shank portion of said gear; f. a worm journalled in said housing means in meshing relation to said gear teeth for driving said gear; and g. manually movable means connected to said worm for rotating said worm; wherein the improvement comprises: h. said gear further including another shank portion disposed on the side of said second portion opposite to said first portion coaxially therewith; i. said housing comprising opposed fixed walls having coaxial openings in which said shank portions of said gear are respectively journalled; j. said second portion including said gear teeth having an external diameter equal to the minimum external diameter of said first portion; and k. each of said shank portions projecting through the housing wall in which it is journalled and being enlarged externally thereof for preventing axial displacement of said gear relative to said housing.
 2. A blind as defined in claim 1, wherein said gear comprises a first body including one of said shank portions and a second body interfitting with said first body and including said second portion and the other of sAid shank portions, said second portion including said gear teeth having an external diameter equal to the minimum external diameter of said other shank portion, and said bodies being respectively inserted through said housing wall openings into interfitting relation to each other.
 3. A blind as defined in claim 1, further including a stop plate fixedly mounted in said head rail adjacent the end of said tilt rod remote from said gear for arresting axial displacement of said tilt rod away from said gear.
 4. In a venetian blind assembly having a plurality of tapes, slats tiltably supported by said tapes, a bottom rail suspended by said tapes beneath said slats and a lift cord secured to the bottom rail at spaced points for lifting said bottom rail, in combination, a. aa head rail; b. a plurality of rolls respectively secured to the upper ends of said plurality of tapes within said head rail; c. means, supported by said head rail, for engaging and supporting each of said rolls within said head rail for rotation about a common axis extending longitudinally of said head rail; d. a tilt rod, extending through and beyond said rolls coaxially therewith, supported by and engaging said rolls such that rotation of said rod rotates said rolls; e. means for locking said lift cord in a selected position, fixedly mounted within said head rail adjacent one end of said tilt rod, said locking means including a fixed plate facing said one end of said tilt rod for arresting axial displacement thereof toward said locking means; f. gear means for rotating said tilt rod, comprising elongated, generally cylindrical structure having first and second shanks and a toothed portion intermediate said shanks aligned in succession along said common axis, said first shank having a socket formed coaxially therein and extending only within said first shank, said socket opening through an end of said first shank and terminating in a seat within said first shank, said toothed portion bearing gear teeth on its outer periphery, said socket receiving and engaging a second end of said tilt rod for rotation therewith and said seat arresting axial displacement of said tilt rod toward said gear, said socket terminating short of the position of said teeth along said common axis, and said toothed portion including said teeth having an external diameter equal to the minimum external diameter of said first shank; g. a housing fixedly mounted in said head rail and rotatably supporting said first and second shanks of said gear means; h. a worm journalled in said housing in meshing engagement with said teeth of said gear means for driving said gear means; and i. manually movable means connected to said worm and depending from said head rail for rotating said worm; j. said first and second shanks respectively projecting beyond said housing in opposite directions and respectively having enlarged ends external to said housing for preventing axial displacement of said gear means relative to said housing.
 5. A blind as defined in claim 4, wherein said gear means structure comprises a first body including one of said shanks, a second body including the other of said shanks and said toothed portion, said toothed portion including said teeth having the same external diameter as said other shank one of said bodies further including a portion interengaging with the other of said bodies for holding said bodies in coaxial relation; and wherein said housing includes opposed end walls having coaxial circular openings through which said bodies are respectively inserted.
 6. A blind as defined in claim 5, wherein said tilt rod and said socket are hexagonal in cross-section.
 7. A blind as defined in claim 4, wherein each of said tapes comprises a pair of flexible stringlike tape elements each having a free upper end with a ferrule secured thereto; and wherein each of said rolls comprises i. a molded rigid plastic body including a cylindrical shank with an axial bore For receiving and engaging said tilt rod, and a central flange projecting radially of the shank, said flange having two peripheral notches, the upper ends of both elements of a tape being respectively inserted in said notches with said ferrules disposed on one side of said flange, said flange further having a radial projection positioned in opposed relation to said notches; and ii. a molded rigid plastic cap press-fitted over said flange from said one side thereof for enclosing the ferrule-bearing ends of the tape elements, said cap having an end with a central opening through which said shank projects, said cap further having a skirt with a notch receiving said radial projection.
 8. In a venetian blind assembly including a. a plurality of tapes each comprising a pair of flexible stringlike tape elements each having a free upper end with a ferrule secured thereto; b. a plurality of slats tiltably supported by said tapes; c. a bottom rail suspended by said tapes beneath said slats; d. a lift cord secured to the bottom rail at spaced points for lifting the bottom rail; e. a head rail; f. a plurality of rolls respectively secured to the upper ends of said plurality of tapes within said head rail; g. means, supported by said head rail, for engaging and supporting each of said rolls within said head rail for rotation about a common axis extending longitudinally of said head rail; h. a tilt rod, extending through and beyond said rolls coaxially therewith, supported by and engaging said rolls such that rotation of said rod rotates said rolls; i. means for locking said lift cord in a selected position; and j. manually operable means for rotating said tilt rod; the improvement which comprises: k. each of said rolls comprising a molded rigid plastic body including a cylindrical shank with an axial bore for receiving and engaging said tilt rod, and a central flange projecting radially of the shank, said flange having two peripheral notches, the upper ends of both elements of a tape being respectively inserted in said notches with said ferrules disposed on one side of said flange, said flange further having a radial projection positioned in opposed relation to said notches; and l. each of said rolls further comprising a molded rigid plastic cap press-fitted over said flange from said one side thereof for enclosing the ferrule-bearing ends of the tape elements, said cap having an end with a central opening through which said shank projects, said cap further having a skirt with a notch receiving said radial projection. 